Field of the Invention
The disclosure relates to a touch display panel and a driving method thereof, and in particular to a touch display panel and a driving method thereof capable of reducing display mura.
Description of the Related Art
The touch display panel is a new type of display panel that integrates the display function and the touch function. In the touch display panel, the panel IC and the touch IC are integrated together. This panel is manufactured in a new process provided by the liquid-crystal panel manufacturer.
In one kind of touch display panel, the common electrode (also called the grounded electrode) is divided into a plurality of electrode blocks which are arranged in a matrix. Each electrode block is used as a normal common electrode in the display period and as a touch sensing electrode in the touch period. The position of a touch object is determined by detecting the capacitance formed between the touch sensing electrode and the touch object.
FIG. 1 is a top view of a conventional touch display panel. As shown in FIG. 1, in a touch display panel 10, the area used to display images is called a display area 11. In the display area 11, the common electrode is divided into a plurality of common electrode blocks S1, S2, . . . , Sk, Sk+1, . . . , and Sm arranged in a matrix. Each common electrode block Sn (n equals to any integer from 1 to m+1) is connected to a driving chip via a metal wire Wn (n equals to any integer from 1 to m+1). The driving chip outputs a common voltage level to all of the common electrode blocks S1, S2, . . . , Sk, Sk+1, . . . , and Sm during the display period, and outputs a touch sensing signal to each common electrode block to determine whether the touch operation is performed during the touch period.
For this kind of touch display panel, the normal driving scheme for a display driving operation and a touch driving operation is a local driving scheme. Specifically, the display area of the panel is divided into a plurality of areas along the column direction, and the areas are driven in sequence. When one area is driven, the area is driven for displaying in a display period and for touch sensing in a touch period in sequence. In the touch period, the gate on panel circuits (also called GOP circuits) pause the outputting of the scan signal for the gate lines. In this way, each area has a pause period in which the scan signal is not supplied. However, for the serial-connected GOP circuits, the scan signal may not be transferred to the next stage because of the pause period. Mura may happen at the boundary of an area driven at the time just before the display period is switched to the touch period or just after the touch period is switched to the display period. Furthermore, because the display period is compressed, GOP circuits may be insufficiently charged and the driving capability is reduced.
In view of the above problems, the disclosure provides a touch display panel and a driving method thereof for solving the problems wherein the signal is not transferred, mura happens at the boundary of the areas, and the driving capability of the GOP circuits is reduced.